Update the language and method names to avoid the term 'shared private'

Author: Brian King

include/swift/AST/AccessScope.h

@@ -30,11 +30,10 @@ class AccessScope {
 
   static AccessScope getPublic() { return AccessScope(nullptr); }
 
-  /// Perform the shared private access check. Private scope is shared between 
-  /// the declaration and all of the extensions of that type inside the file.
-  /// This will return false in Swift 3 mode because private is not shared
-  /// between types.
-  static bool checkSharedPrivateAccess(const DeclContext *useDC, const DeclContext *sourceDC);
+  /// Check if private access is allowed. This is a lexical scope check in Swift
+  /// 3 mode. In Swift 4 mode, declarations and extensions of the same type will
+  /// also allow access.
+  static bool allowsPrivateAccess(const DeclContext *useDC, const DeclContext *sourceDC);
 
   /// Returns nullptr if access scope is public.
   const DeclContext *getDeclContext() const { return Value.getPointer(); }
@@ -54,8 +53,7 @@ class AccessScope {
   /// \see DeclContext::isChildContextOf
   bool isChildOf(AccessScope AS) const {
     if (!isPublic() && !AS.isPublic())
-      return (getDeclContext()->isChildContextOf(AS.getDeclContext()) ||
-        checkSharedPrivateAccess(getDeclContext(), AS.getDeclContext()));
+      return allowsPrivateAccess(getDeclContext(), AS.getDeclContext());
     if (isPublic() && AS.isPublic())
       return false;
     return AS.isPublic();

lib/AST/DeclContext.cpp

@@ -970,13 +970,13 @@ Accessibility AccessScope::accessibilityForDiagnostics() const {
   return Accessibility::Private;
 }
 
-/// Return the DeclContext to compare when checking shared private access in
-/// Swift 4 mode. The shared scope is the type declaration if the context
+/// Return the DeclContext to compare when checking private access in
+/// Swift 4 mode. The context returned is the type declaration if the context
 /// and the type declaration are in the same file, otherwise it is the types
 /// last extension in the source file. If the context does not refer to a
 /// declaration or extension, the supplied context is returned.
 static const DeclContext *
-getSharedPrivateDeclContext(const DeclContext *DC, const SourceFile *useSF) {
+getPrivateDeclContext(const DeclContext *DC, const SourceFile *useSF) {
   auto NTD = DC->getAsNominalTypeOrNominalTypeExtensionContext();
   if (!NTD)
     return DC;
@@ -996,8 +996,12 @@ getSharedPrivateDeclContext(const DeclContext *DC, const SourceFile *useSF) {
   return lastExtension ? lastExtension : DC;
 }
 
-bool AccessScope::checkSharedPrivateAccess(const DeclContext *useDC, const DeclContext *sourceDC) {
-  // Shared private scope is not performed in Swift 3 mode.
+bool AccessScope::allowsPrivateAccess(const DeclContext *useDC, const DeclContext *sourceDC) {
+  // Check the lexical scope.
+  if (useDC->isChildContextOf(sourceDC))
+    return true;
+
+  // Only check lexical scope in Swift 3 mode
   if (useDC->getASTContext().isSwiftVersion3())
     return false;
 
@@ -1008,10 +1012,10 @@ bool AccessScope::checkSharedPrivateAccess(const DeclContext *useDC, const DeclC
   if (useSF != sourceDC->getParentSourceFile() || !sourceNTD)
     return false;
 
-  // Compare the shared private scopes and iterate over the parent types.
-  sourceDC = getSharedPrivateDeclContext(sourceDC, useSF);
+  // Compare the private scopes and iterate over the parent types.
+  sourceDC = getPrivateDeclContext(sourceDC, useSF);
   while (!useDC->isModuleContext()) {
-    useDC = getSharedPrivateDeclContext(useDC, useSF);
+    useDC = getPrivateDeclContext(useDC, useSF);
     if (useDC == sourceDC)
       return true;
 

lib/AST/NameLookup.cpp

@@ -1263,8 +1263,7 @@ static bool checkAccessibility(const DeclContext *useDC,
   switch (access) {
   case Accessibility::Private:
     return (useDC == sourceDC ||
-      useDC->isChildContextOf(sourceDC) ||
-      AccessScope::checkSharedPrivateAccess(useDC, sourceDC));
+      AccessScope::allowsPrivateAccess(useDC, sourceDC));
   case Accessibility::FilePrivate:
     return useDC->getModuleScopeContext() == sourceDC->getModuleScopeContext();
   case Accessibility::Internal: {